The question of environmental responsibility is addressed through comparisons between Hannah Arendt’s and Ulrich Beck’s accounts of the emergent and globally threatening risks associated with acting into nature. Both theorists have been extraordinarily influential in their respective fields but their insights, pointing toward the politicization of nature through human intervention, are rarely brought into conjunction. Important differences stem from Beck’s treatment of risks as systemic and unavoidable side effects of late modernity. Arendt, however, retains a more restrictive anthropogenic view of political action which, while recognizing its unpredictable consequences for human (and nonhuman) others, includes a direct link between individually initiated acts and the taking of ethical responsibility. This latter account best explains the ethical motivations behind much environmental activism